Urea is a component of urine, mainly the product of protein metabolism, which is harmful to human body and must be excreted to avoid the symptoms of poisoning. Generally, the value of urea is about 0.3g, and the content of urea can reach one tenth of that of urine. If the urea content increases, it is generally because of water shortage or insufficient blood volume, and the existence of nephritis will also cause the increase of urea.
Urea is the final product of protein metabolism in human body, which is excreted with urine mainly through glomerular filtration, so urea can reflect the filtration function of glomerulus.